Because I think the Celebrity series is not well made and they don't sound good. This is just my opinion, of course. They were relatively inexpensive a few years ago, I believe, and seemed to be the "budget" line Ovation. Somehow people's memories have failed them over the years and these guitars are now by some freak of nature considered a real type of model for Ovation - the price reflects that, too. The price is up, I believe.
I mean no offense to owners of the Celebrity series. I own an Ovation from 1974. It kicks MAJOR ASSSSSSSSSS. And, even a couple of years ago it didn't cost me much more than most people probably are paying for their Celebrity series instruments now.
LL